SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34c7d199fb11113eb532bd92ea3ae1ecbf200a9dcfb3bfad752a2cc23c5d2769' 
  AND token = 'X+UEqQz0MheWwsSy4FC2FPMdRZvi5g6JgWiiXNvAgFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}